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DMA-80

Direct Mercury Analyzer

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Introduction

Mercury in the atmosphere can

be from manmade sources

(coal-fired power plants,

municipal incinerators,

industrial boilers) or from

natural sources (forest fires,

geologic formations,volcanoes)

Precipitation is the primary

mechanism for transporting

airborne gaseous or particulatemercury from the atmosphere

to surface water and land


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Mercury Analysis


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Aqueous samples

and extractsASV7472

Solid or semi-solid

wasteCV-AAS7471A

Liquid wasteCV-AAS7470A

Sample typeTechniqueMethod


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CV-AAS

Cold Vapor-Atomic Absorption Spectroscopy

Samples are digested or dissolved

Mercury is reduced to free atomic state by using tin

(II) chloride or sodium boro-hydride in a closed

reaction vessel Mercury is measured by atomic absorption


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CV-AAS

Few minutesAASAnalysis

Mercury reduction

1 hour

Interference removal

Wet chemistry

20 minutes- 1 hourClosed vessel

microwave

2 hours- 2 daysHot plate

Sample acid digestion

TimeDescriptionStep


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CV-AAS and ASV

Both methods require sample digestion and

further wet chemistry Sample digestion can be problematic because

of Hg volatility

Sample preparation is the bottleneck for higheranalytical productivity


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DMA-80



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DMA-80 Advantages

Direct Hg determination at trace level on solid

and liquid samples No sample digestion step

No wet chemistry pre-treatment step

Fast, approximately 6 minutes per sample

Eliminates waste disposal

Validated results (US EPA method 7473) forsolid and liquid matrices


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DMA-80

Principle of operation

Solid or liquid samples are weighed and introduced in

the DMA-80 The sample is initially dried and then thermally

decomposed in a oxygen flow

Combustion products are carried off and further

decomposed in a hot catalyst bed

Mercury vapors are trapped on a gold amalgamator and

subsequently desorbed for quantitation

The mercury content is determined using atomicabsorption spectrophotometry at 254 nm


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DMA-80

Major components

Sample dosing system Thermal process furnaces

Atomic absorption spectrophotometer

System controller


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Sample Dosing System

Built-in 40 position auto-sampler for high

throughput unattended operation, for solid andliquid samples

Maximum sample weight 500 mg

Maximum sample volume 500 l

Possibility of multiple sample dosing for Hg pre-

concentration on amalgamator


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Sample Introduction


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Fully Loaded Autosampler


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Pipetting Liquid Samples


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Thermal process


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Thermal Process

12 s0-30 s900C850-950CAmalgam

600C550-650CCatalysis

180 s0-420 s

850C800-1.000CDecomposition

60 s0-300 s300C20-300CDrying

Typical timeTime rangeTypical

temperature

Temperature

rangeStep


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Oxygen

Research grade

(O2 > 99,95%)Purity

200 ml/minuteFlow rate

4 bar (60 psig)Inlet pressure

Carrier and decomposition

gasFunction


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Atomic Absorption

Spectrophotometer


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AAS Technical Data

Si-photodiode sensorDetector

254 nm, 9 nm bandwidthInterference filter

253,65 nmWavelength

Low pressure mercury lampLight source

Single beam spectrophotometer

with sequential flow through of

measurement cells

Instrument optics


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Typical Absorbance Profile


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DMA-80

Performance Specifications

(1)Sample weight 100 mg(2)Automatic switching when absorbance 0,8

0,20,02Detection limit

(1st) 0,2-350

(2nd) 350-6.000

(1st) 0,02-35

(2nd) 35-600Working range(2)

Hg concentration(1)

(g/kg)Total Hg (ng)Data


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DMA-80

Performance Specifications

6 minutesTypical analysis time

< 1,5%Typical reproducibility


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System controller

Lab TERMINAL

Touch-screen Pentium-based controller, 266 MHz, 64MB Ram, Windows 98, Color 12,1 TFT SVGA

monitor, CD-ROM, FD, Smart Card Reader, 2 COM,

1 USB, LAN ports

Standard bench-top computer with similar

specifications

Dedicated Terminal 1024


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EasyControl Software

Evolution of previous Windows based DMA-80

software Selectable calibration algorithm

Virtually unlimited memory for programs and

actual data storage Built-in service and diagnosis functions

CFR-21 part 11 compliant


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System Status


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1st

Cell Linear Calibration


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1st

Cell Square Calibration


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Measurement/Graphic


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Balance Setup


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History Trail CFR 21 Part 11


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Mercury Trap

Optional mercury trap tobe located at DMA-80

outlet

Activated charcoal Safe operation

Easy and ready to install


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DMA-80Analytical Performance


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Getting Started Oxygen cylinder with gas regulator stable at 4 bar (60

psig)

Power 115-230 V/50-60 Hz

Analytical balance with serial interface

Windows compatible printer

Standard reference materials

Aqueous standards

Precision pipettes


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DMA-80 Calibration


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DMA-80 Calibration Liquid standards

Different concentrations, same volume Same concentration, different volumes

Use fresh standards, stabilized with HNO3 orHCl/K2Cr2O7

Solid standards Certified mercury content

Vary by weight


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0 ng


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10 ng


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20 ng


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30 ng


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100 ng


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200 ng


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500 ng


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Calibration 1st

Cell

0,6%0,722330 ng

1,2%0,499620 ng

2,2%0,254910 ng

1,5%0,12725 ng

16,7%0,0012Blank

RSD (n=3)AbsorbanceSolution


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Calibration 2nd

Cell

0,9%0,7285500 ng

1,9%0,3117200 ng

2,2%0,1546100 ng

RSD (n=3)AbsorbanceSolution


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Calibration Curves


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DMA-80 Accuracy


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Certified Reference Materials

6.250 190NIST 2711 Soil

1.400 80NIST 2709 Soil

141 19NIST 1633b Fly Ash

93,8 3,7NIST 1630a Coal

34 4NIST 1573a Tomato Leaves

5,8 0,5NIST 1568a Rice Flour

Hg content (g/kg)Sample


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NIST 1568a Rice Flour

2,0

3,0

4,0

5,0

6,0

7,08,0

Hg(g/kg)

Certified DMA-80


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NIST 1573a Tomato Leaves

24,0

28,0

32,0

36,0

40,0

Hg(g/kg)

Certified DMA-80


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NIST 1630a Coal

80,0

85,0

90,0

95,0

100,0

Hg(g/kg)

Certified DMA-80


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NIST 1633b Fly Ash

100,0

120,0

140,0

160,0

180,0

Hg(g/kg)

Certified DMA-80


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NIST 2709 Soil

1,0

1,2

1,4

1,6

1,8

Hg(mg/kg

Certified DMA-80


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NIST 2711 Soil

5,8

6,0

6,2

6,4

6,6

Hg(

mg/kg)

Certified DMA-80


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DMA-80 Precision


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Fresh Salmon


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Collecting Sample


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Weighing


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Loading Autosampler


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Loading Furnace


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After Analysis

Fresh Salmon


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Fresh Salmon

56,20,29925

58,00,34044

57,80,23303

54,10,22962

55,40,28491

Hg (g/kg)Weight (g)Run

Fresh Salmon


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Fresh Salmon

5N

1,6Sd (g/kg)

56,3Average (g/kg)


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DMA-80 Detection Limit

Detection Limit


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Detection Limit

The detection limit is defined as the concentration which

will give an absorbance signal of two (sometimes three)

times the magnitude of the baseline noise. The baseline

noise may be statistically quantified typically by making

ten or more replicate measurements of the baseline

absorbance signal observed for an analytical blank, anddetermining the standard deviation of the

measurements. The detection limit is then defined as the

concentration which will produce an absorbance signal

twice (or three times) the standard deviation

Detection Limit


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Detection Limit

0,0006100,00075

0,000890,00084

0,001080,00063

0,000870,00102

0,001060,00071

AbsorbanceRunAbsorbanceRun

Detection Limit


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Detection Limit

0,02 ngDL

0,0004683*Sd

0,000156Sd

0,0008Average


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DMA-80 Memory Effect



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0,40,0097 (1st)Blank 2

1,50,0374 (1st)Blank 1

500 (set)0,7285 (2nd)Standard 500 ng

Mercury content (ng)AbsorbanceSample



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DMA 80 Memory Effect

Quartz Boats


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Quartz Boats

Analysis of liquids with

DMA-80 autosampler

Improved performance

Lower memory effect

Better reproducibility

Longer life time

Quartz vs. Metal Boats


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Quartz vs. Metal Boats

0

0,1

0,2

0,3

0,4

1 2 3 4 5 6 7 8 9 10Run

Signal

Metal Quartz

Memory Effect


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Memory Effect

0,010,000,0000,1001

0,450,050,00110,1001

1.106,01110,600,14740,1001

Result

(g/kg)Hg (ng)HeightWeight (g)Sample ID

Reproducibility at Low


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Concentrations

AVG 8,55SD 0,09 g/kgRSD 1,01%Statistics

8,500,850,02170,100

8,490,850,02160,100

8,510,850,02170,100

8,530,850,02180,100

8,720,870,02220,100

Results (g/kg)Hg (ng)HeightWeight (g)

Reproducibility at High


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Concentrations

AVG 1.143,7RSD 0,69%SD 7,88 g/kgStatistics

1.143,4114,340,15230,100

1.158,7115,870,15430,100

1.141,3114,130,15200,100

1.136,2113,620,15140,100

1.138,8113,880,15170,100

Results (g/kg)Hg (ng)HeightWeight (g)

Lifetime


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US EPA method 7473 Mercury in solids and solutions by thermal

decomposition amalgamation and atomic absorption

spectrophotometry


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ComparisonDMA-80 vs. CV-AAS

Comparison


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DMA-80 vs. CV-AAS

YesMinimalWaste generation

Yes, to eliminate

interferencesNot requiredWet chemistry

ElevatedModerateRunning cost

Limited to low rangeUp to 600 ngWorking range

100 ml solutionUp to 500 mg sampleSample size

AqueousLiquid and solidsSample type

Acid digestionNot requiredSample preparation

CV-AASDMA-80Technique

Time Comparison


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DMA-80 vs. CV-AAS

0

60

120

180

240

DMA-80 CV-AAS

Tim

e(minutes

Sample preparation Analysis

DMA-80 Major Applications


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Biological Blood, urine, hair, tissue, plankton

Liquids Waste water, crude oil, heavy oil, detergents, paints

Solids Coal, fly ash, soil, sediment, sludge, minerals, food, feed, plastic,

wood, vegetables, leaves, waxes Medicinal

Pharmaceuticals, gelatin capsules, lipstick, lotions

DMA-80


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